The present invention relates to a method and apparatus for fitting component sections together, and more particularly to a method and apparatus for fitting two component sections together and temporarily holding them together prior to assembling the component sections together rigidly into the whole integrated body with coupling bolts in an automatic assembling line.
Various methods and apparatus have heretofore been used to fit together two component sections, for example, an engine cylinder block and its cylinder head, with a high accuracy of registry relative to each other prior to rigidly fixing, and thereby assembling, the two component sections with coupling bolts into one whole integrated body.
One such apparatus is disclosed in Japanese Patent Publication No. 56-20,135, entitled "Automatic Assembling Apparatus," issued May 12, 1981. In the apparatus taught by the above-mentioned Japanese patent publication, one component section having at least two locating pins is placed on the other component section in proper registry by fitting the locating pins in corresponding recesses formed in the other component section. This fitting is well known in the art as a locating pin fitting method.
Another known method is a so-called faucet fitting method in which spigots having a certain shape are formed on one component section and are fitted into complementarily shaped sockets formed in the other component section to set up the two component sections in proper registry relative to each other.
When employing any method of the above type wherein two component sections are fitted together in proper registry prior to being rigidly fixed, and thereafter being assembled into one body, by means of a plurality of tightening elements such as coupling bolts, a serious problem exists when the two component sections are assembled into one complete body with the aid of, in particular, an industrial robot or a manipulator in an automatic assembling line. Any error of registry between the two component sections results in an improper fitting or a mis-fitting between the spigot and its associated socket or the locating pin and its associated recess. If the two component sections fitted together are transferred either directly or indirectly to a next step, for example, a fixing step, of an automatic assembling process while an improper fitting or a mis-fitting still exists between the spigot and its associated socket or the locating pin and its associated recess, there rises a great possibility that one component section will accidentally slip off from the other and fall down during the transferring thereof.
For getting the highest state of efficiency in assembling the component sections into one whole body, an industrial robot or a manipulator is widely used to set a plurality of coupling bolts in one or both component sections one by one. Such an industrial robot or a manipulator has a bolt gripping hand provided with clamping fingers, which clamping fingers are adapted to open and close in order to clamp and unclamp a coupling bolt. Upon inserting the coupling bolt into a bolt receiving bore or bolt hole in a component section, the clamping fingers open to unclamp the coupling bolt, permitting it to fall into the bolt receiving bore. Because the component sections generally have complicated rugged outer configurations, and because the opening of the bolt hole through which the coupling bolt is being inserted is often recessed, the bolt gripping hand, in particular the bolt clamping finger, of a manipulator may interfere with the opening of the bolt receiving bore when the bolt clamping fingers open to unclamp the coupling bolt. Also, the clamping fingers themselves and/or the component section is liable to be damaged during setting of the bolts in the bolt holes.
Furthermore, since ordinary machine bolts come in various types of polygonal heads, for example, octagon heads, clamping the bolt head positively between the clamping fingers of the gripping hand of the robot or the manipulator is difficult. Uncertain clamping results in unsuccessful setting of coupling bolts in counter bores.